title: Energy-independent uptake of iron from citrate by isolated outer membranes of Neisseria meningitidis.
abstract: Cyanide-poisoned Neisseria meningitidis SD1C cells rapidly took up 55Fe from iron-citrate complexes during the first 2 min, after which no further iron was accumulated. [14C]citrate was not taken up concomitantly with 55Fe by these cells. The 55Fe taken up by the poisoned cells was found in the membrane fraction after cells were broken; 70% of the radioactivity was distributed in the outer membrane, and 30% was in the inner membrane. Isolated outer membranes from iron-starved cells were as capable of iron uptake from citrate as intact cells were. As with whole cells, [14C]citrate was not taken up by isolated outer membranes. A polyacrylamide gel electrophoresis analysis of the proteins from citrate-dialyzed outer membranes after the uptake of 55Fe revealed that the radioactivity was associated with a major band of 36,500 molecular weight.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002474:Cell-Free System; D002951:Citrates / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins; D008565:Membrane Proteins / Q000378:metabolism; D008970:Molecular Weight; D009345:Neisseria meningitidis / Q000378:metabolism*; D033863:Transferrin-Binding Proteins
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002951:Citrates; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D033863:Transferrin-Binding Proteins; D007501:Iron